KR20080043735A - Oct using spectrally resolved bandwidth - Google Patents

Abstract

A system for optical coherence tomographic imaging of turbid materials utilizing multiple channels of information comprising spatial, angle, spectral and polarization domains. The multichannel optical coherence tomographic methods can be incorporated into an endoscopic probe for imaging a patient. The endoscope comprises an optical fiber array and can comprise a plurality of optical fibers adapted to be disposed in the patient. The optical fiber array transmits the light from the light source Into the patient, and transmits the light reflected by the patient out of the patient. The plurality of optical fibers in the array are in optical communication with the light source. The multichannel optical coherence tomography system comprises a detector for receiving the light from the array and analyzing the light. The methods and apparatus may be applied for imaging a vessel, biliary, GU and/or Gl tract of a patient.

Description

OCT USing Spectrally Decomposed Bandwidth {OCT USING SPECTRALLY RESOLVED BANDWIDTH}

The present invention relates to a system for optical coherence tomographic imaging of turbid (ie, scattering) material using multiple channels of information. Multiple channels of information may be included and may include spatial domain, angular domain, spectral domain, and polarization domain. More particularly, the present invention provides an optical source capable of providing a plurality of channels of spectral information for optical coherence tomographic imaging of cloudy materials, a processable system, or a method capable of recording a receiver. And to an apparatus. In such a method and apparatus, a plurality of channels of spectral information, which may be provided by a source, processed by a system, or recorded by a receiver, may include spatial information associated with a cloudy material imaged by tomography, It is used to carry spectral information, or polarimeter information simultaneously.

The multichannel optical coherence tomography method can be integrated into an endoscope probe for imaging a patient. The endoscope may include an optical fiber array and may include a plurality of optical fibers suitable for placement in the patient body. The optical fiber array delivers light from the light source to the patient and delivers light reflected by the patient from the patient. The plurality of optical fibers in this array are in optical communication with the light source. The multichannel optical coherence tomography system includes a detector for receiving light from the array and analyzing the light. The method and apparatus may be applied to image a patient's blood vessels, bile ducts, GU and / or GI organs.

Myocardial infarction or heart failure is the leading cause of death in our society. Unfortunately, most of us can see family members or close friends suffering from myocardial infarction. Until recently, many researchers knew that coronary arteries that were critically blocked by atherosclerosis plaques that continued to full occlusion were the main mechanisms for myocardial infarction. However, recent evidence from many investigative studies clearly shows that most infarcts are due to sudden rupture of non-critically constricted coronary arteries due to sudden plaque rupture. For example, Little and colleagues (Little, WC, Downes, TR , Applegate, RJ The underlying coronary lesion in myocardial infarction:.. Implications for coronary angiography Clin Cardiol 1991; 14: 868-874, which is incorporated herein by reference), indicates that approximately 70% of patients suffering from acute plaque rupture are initiated on occluded plaques less than 50% as revealed by previous coronary angiography. Observed. These and similar observations were confirmed by other researchers (Nissen, S. Coronary angiography and intravascular ultrasound. Am J Cardiol 2001; 87 (suppl): 15A-2OA, which is incorporated herein by reference).

Developing a technique to identify these labile plaques can substantially reduce the incidence of acute coronary syndrome, which often leads to premature death. Unfortunately, no method has been available to the cardiologist to date which can be applied to specify which coronary plaques are fragile and therefore rupturable. Although treadmill testing has been used to identify patients at greater cardiovascular risk for many years, this method has the specificity to distinguish between stable plaques and fragile plaques that are prone to rupture and often cause myocardial infarction. Do not. Because there is a great deal of information about the pathology of unstable plaques (determined in the body anatomy), techniques based on identifying well-described pathological phenomena of plaques that are susceptible to damage are promising to solve these problems. Allows you to develop a strategy for the period.

Unstable plaques were first identified and characterized by pathologists in the early 1980s. Davis and colleagues found that reconstruction of sequential histological sections in patients with acute myocardial infarction associated with death was evident in rupture or division of atherosclerotic plaques (Davis MJ, Thomas AC. Plaque fissuring: the cause of acute myocardial infarction, sudden death, and crescendo angina Br Heart J 1985; 53:. 363-373, which incorporated herein by reference). Ulcerous plaques also have a thin fibrous cap and are characterized by having increased macrophages with reduced smooth muscle cells and increased fat nuclei when compared to non-ulcerative atherosclerotic plaques in the human aorta. (Davis MJ, Richardson PD, Woolf N, Katz DR, Mann J. Risk of thrombosis in human atherosclerotic plaques: role of extracellular lipid, macrophage, and smooth muscle cell content, which is incorporated herein by reference). In addition, no correlation between the size of the lipid pool and the percent stenosis is observed when imaged by coronary angiography. In fact, most cardiologists agree that unstable plaques progress to more narrowed but stable plaques by progression through rupture with wall thrombus formation and plaque remodeling but without complete luminal occlsion (Topol EJ). , Rabbaic R. Strategies to achieve coronary arterial plaque stabilization Cardiovasc Res 1999; 41:. 402-417, which incorporated herein by reference). Neovascularization with internal plaque bleeding can also serve to make this progression from minor injuries (obstructed to <50%) to larger and more pronounced plaques. However, if the inherent characteristics of unstable plaques are recognized and then stabilized by a cardiologist, dramatic reduction can be realized in both acute myocardial infarction and unstable angina syndrome, and in the rapid progression of coronary artery disease. Can be.

The present invention uses pathology-resolved light reflection or optical coherence tomography (OCT) to identify pathological features identified in plaques that are susceptible to damage. In OCT, light from a wide band light source or a tunable laser source is input to an interferometer, with some of the light directed towards the vessel wall and another toward the reference surface. The ends of the optical fiber interface with the catheter for the invocation of the coronary artery during the cardiac catheterization procedure. Reflected light from the plaque recombines with the signal from the reference surface and forms an interference fringe (measured by a photovoltaic detector) to enable precise depth-resolution imaging of the plaque on a micron scale.

OCT uses epithelial tomographic images with 10-20 μm axial resolution and 2-3 mm tissue penetration using either high-brightness diode source-emitting light or narrow linewidth tunable laser sources over a wide bandwidth (wavelength distribution). Make OCT can image tissue at the level of a single cell. In fact, the inventors have recently used wider bandwidth optical sources, such as femto-second pulsed lasers, so the axial resolution has improved to less than 4 microns. With this resolution, the OCT can be applied to visualize details of the structure, including the intima cap, their thickness, and cracks, the size and width of the underlying fatty pool, and the presence of inflammatory cells. Moreover, near-infrared light sources used in OCT instruments can penetrate heavily calcified tissue areas that are characterized by advanced coronary artery disease. With cellular resolution, the application of OCT can be used to identify other details of susceptible plaques such as monocytes and macrophages. In short, the application of OCT can provide a detailed image of a pathological specimen without cutting or obstructing tissue.

One concern in the application of this technique to imaging atherosclerotic plaques in the arterial lumen is the strong scattering of light due to the presence of red blood cells. If the catheter system is located in the coronary artery, the blood flow between the OCT fiber and the artery can obscure light penetration into the vessel wall. One solution proposed is the use of saline flush. But salt use is limited in duration because myocardial ischemia eventually occurs in the terminal myocardium. The inventors proposed the use of artificial hemoglobin instead of saline. Artificial hemoglobin is non-particulate and therefore does not scatter light. Moreover, artificial hemoglobin has just been approved as a blood substitute by the US Food and Drug Administration and can carry the oxygen needed to prevent myocardial ischemia. Recently, the inventors have demonstrated the possibility of using artificial hemoglobin to reduce light scattering by blood in rat myocardial coronary arteries (Villard JW, Feldman MD, Kim Jeehyun, Milner TE, Freeman GL. Use of a blood substitute to determine instantaneous murine right ventricular thickening with optical coherence tomography Circulation 2002; Volume 105:. Pages 1843-1849, which incorporated herein by reference).

The first prototype of the OCT catheter for imaging coronary plaques has been established and in collaboration with Light Lab Co., researchers at Harvard-MIT, Boston (Jang IK, Bouma BE, Kang DH, et al. Visualization of coronary atherosclerotic plaques) in patients using optical coherence tomography: comparison with intravascular ultrasound.JACC 2002; 39: 604-609, which is incorporated herein by reference). A prototype catheter consists of a single light source and can image the arc of the coronary lumen 360 degrees by rotating a shaft that turns the optical fiber. Since the rotating shaft is housed out of the body, the revolving rod in the catheter must rotate at a constant angular velocity so that the light can be focused for the same time interval on each angular segment of the coronary artery. Mechanical drag on the rotating shaft can create significant distortions and artifacts in the recorded OCT image of the coronary arteries. Unfortunately, the catheter is always forced to make several bends between the entry points in the femoral artery to the coronary artery (eg, turn 180 degrees around the aortic arch), resulting in uneven mechanical drag. ) Results in an OCT image artifact. As the application of OCT shifts from imaging the entire anatomical structure of the coronary arteries to the ability to image at the level of a single cell, non-uniform rotation of single fiber OCT prototypes causes distortion and an increasing problem of image artifacts. do.

In essence, the current endoscope type single channel OCT system developed by Light Lab Co. suffers from the inconsistent rotational speed that forms an abnormal image of the vascular target. See US Pat. No. 6,134,003, which is incorporated herein by reference. Their way of using a rotating shaft to spin single-mode fibers is easy to make artifacts. The catheter must always make several bends from its entry in the femoral artery to its final destination in the coronary artery with a 180 degree turn around the aortic arch. All these bends cause non-uniform friction on the rotating shaft and cause a non-uniform time distribution of light on the entire 360 degree arch of the coronary artery. As the application of OCT shifts from the entire anatomical structure of the coronary arteries to the ability to image at the level of a single cell, the non-uniform rotation of a single fiber OCT is a greater cause of even larger artifacts.

The present invention solves rotational distortion and related artificial problems by developing a multiphase array OCT catheter. By integrating 10-60 individual OCT fibers in a single catheter, rotation of the optical fiber or similar device (eg, micro-motor drive mirror) and its associated image distortions and artifacts can be eliminated and spatial resolution can be improved. The catheter may allow 10-60 individual light sources to individually image the 360 degree arc of the coronary lumen. An additional advantage of multiphase arrays is that they provide greater spatial resolution of the studied object compared to a single fiber design. Many researchers recognize that the multiphase array method can provide cellular resolution, while the single rotating fiber or micro-motor driven mirrors used in recent designs do not allow imaging at the level of a single cell.

In constructing a multiphase array OCT catheter, many problems must be solved using innovative design solutions. Successful design and demonstration of the catheter requires the development of an optical channel containing 10-60 individual fibers 1.5 mm in diameter. Each fiber requires a mirror made using nanotechnology to redirect light from each fiber from the catheter to the luminal surface of the coronary artery and a lens for focusing the light. Furthermore, each of the 10-60 optical paths must be separated again for both the reference path and the arterial path. The present invention provides a design solution for both catheters and multichannel interferometers.

The present invention relates to an endoscope for a patient. This endoscope includes means for producing light, such as a light source. The endoscope includes an optical fiber array comprising a plurality of optical fibers configured to be placed in the body of a patient. This optical fiber array transmits light from the means for generating light to the patient and transmits light reflected from the patient by the patient. The plurality of optical fibers of the optical fiber array are in optical communication with the means for generating light. The endoscope includes a detector for receiving light from the optical fiber array and analyzing the light. The plurality of optical fibers of the optical fiber array are in optical communication with the detector.

The present invention relates to a method of imaging a patient. The method includes transmitting light from a light source to an optical fiber array comprising a plurality of optical fibers in a patient's body. There is a step of transmitting the light reflected by the patient from the patient. There is a step of receiving light from an optical fiber array at a detector. There is a step of analyzing this light using a detector.

The present invention relates to an apparatus for irradiating an object. The apparatus includes means for generating light. The apparatus includes means for analyzing light reflected from the object based on polarization, space, position or angle.

The present invention relates to an apparatus for irradiating an object. The apparatus includes means for generating light. The apparatus includes means for analyzing light reflected from the object based on polarization.

The present invention relates to an apparatus for irradiating an object. The apparatus includes means for generating light. The apparatus includes means for analyzing light reflected from the object based on space.

The present invention relates to an apparatus for irradiating an object. The apparatus includes means for generating light. The apparatus includes means for analyzing light reflected from the object based on the angle.

The present invention relates to a method of examining an object. The method includes generating light. The method includes analyzing light reflected from an object based on polarization, space, position or angle.

The present invention relates to a method of examining an object. The method includes generating light. The method includes analyzing light reflected from an object based on polarization.

The present invention relates to a method of examining an object. The method includes generating light. The method includes analyzing light reflected from an object based on space.

The present invention relates to a method of examining an object. The method includes generating light. The method includes analyzing light reflected from the object based on the angle.

In the accompanying drawings, preferred embodiments of the invention and preferred methods of practicing the invention are illustrated.

1 is a schematic representation of an overview of the invention.

2 is a plan view of an input arm (light source) of the present invention.

3 schematically illustrates a side view of an input arm (light source).

4 diagrammatically illustrates a fiber based solution for the input arm.

5 schematically illustrates a side view of a sample arm.

6 is a schematic representation of an axial view of a sample arm.

7 shows a plan view of an axicon lens.

8 schematically illustrates an optical fiber array of sample arms.

FIG. 9 schematically shows a perspective view of a probe tip of a sample arm enphasing a mirror to refocus light on the tissue.

각도의 미러(반사)로 마무리된 부착된 섬유를 갖는 팁의 그루브(groove)의 측면도를 도식적으로 나타낸 것이다.10 is 45

A schematic side view of a groove of a tip with attached fibers finished with an angled mirror (reflection) is shown.

11 shows a plan view of a tip with attached fibers.

12 shows diagrammatically a first step in the manufacture of each fiber lens of a sample arm.

13 shows schematically a second step in the manufacture of each fiber lens of the sample arm.

Figure 14 schematically shows a reference arm of the present invention.

15 schematically shows a plan view of the detection arm of the present invention.

16 schematically shows a side view of a detection arm.

17 shows an alternative schematic diagram of a scanning probe of a sample arm.

18A and 18B schematically illustrate a hydraulic mechanism.

19A and 19B schematically show exploded views of the hydraulic mechanism.

20A-20D diagrammatically show different views of a twisted shaft of a hydraulic mechanism.

21A and 21B diagrammatically illustrate a fiber-shaft holder.

22A-22C diagrammatically show fiber grooves.

23 is a side view of the micro-mirror.

24 is a perspective view of a micro-mirror.

25 is a perspective view of a micro-mirror with portions irradiated by a laser beam.

FIG. 26 is a perspective view of a micromirror with deformations caused by irradiation with a laser beam as shown in FIG. 25.

Figure 27 schematically shows a micro-mirror which is continuously heated by a laser beam projected on different positions of the micro-mirror.

FIG. 28 diagrammatically shows the resulting change in the tilting direction of the micro-mirror due to changing the position of the laser beam on the micro-mirror.

29 schematically shows a micro-mirror in a probe cover for a fiber.

30 is a graphical representation of micro-mirror movement for a fiber.

FIG. 31 is a schematic representation of single channel fiber-based polarization sensing spectral domain optical interference tomography with a Fiber Optic Spectral Polarimetry Instrument (FOSPI).

FIG. 32 schematically illustrates fiber-based spatially multiplexed and swept source optical coherence tomography.

33 schematically shows a multi-fiber angle-domain OCT.

34 and 35 are images recorded using a spatially multiplexed OCT system.

36 and 37 are phase delays due to birefringence and fast-axis angle, respectively.

Referring now to the drawings, an endoscope 10 for a patient is shown, wherein like reference numerals refer to like parts or like parts in more detail with respect to FIGS. 1 to 5, 15, and 16 through some figures. . Endoscope 10 includes means 102 for generating light, such as light source 51. Endoscope 10 includes an optical fiber array 28 that includes a plurality of optical fibers 8 adapted to be placed in a patient's body. The optical fiber array 28 transmits the light from the means, preferably the light source 51, to the patient and the light reflected by the patient from the patient. The plurality of optical fibers 8 of this array 28 are in optical communication with the means 102 for generating light. Endoscope 10 includes a detector for receiving light from array 28 and analyzing the light. The plurality of optical fibers 8 of the array 28 are in optical communication with the detector D.

Preferably, the endoscope 10 comprises a tube 53, with a plurality of optical fibers 8 arranged around the tube. This tube 53 preferably has grooves 54 extending longitudinally along the tube 53 as shown in FIG. 10. One of the plurality of optical fibers 8 is disposed in each of the grooves 54. Preferably, endoscope 10 includes a probe probe tip 55 having a reflector 56 disposed in each groove, as shown in FIG. 11, which reflector 56 includes a reflector ( 56 reflects light from the optical fiber 8 in the groove when in the patient body and reflects light from the patient to the optical fiber 8 when the array 28 is in the patient body.

The light source 51 preferably comprises a coherent light source 51 and comprises means 57 for guiding light from the light source 51 to the plurality of optical fibers 8 of the array 28. . Preferably, as shown in FIGS. 12 and 13, the optical fiber 8 is single mode and has a core 118 having a cladding 120, where the cladding 120 is a core. Disposed around 118, the tip having a lens 122 for focusing light from core 118 to reflector 56 and focusing light from reflector 56 to core 118. . Array 28 preferably comprises a transparent cover 7.

Preferably, the light source 51 comprises an input arm 58, the array 28 comprises a sample arm 59, and the detector D comprises a reference arm. arm 60 and detector arm. The input arm 58, the detector arm 61, the sample arm 59, and the reference arm 60 together form an interferometer with each other. Reference arm 60 preferably uses RSOD to introduce depth scanning and dispersion compensation for the interferometer.

Preferably, the endoscope 10 has an opto-optocoupler that optically connects the input arm 58, the sample arm 59, the reference arm 60, and the corresponding optical fibers 8 of the detection arm with one another. -coupler 62). The detector D is preferably structural to the patient from the intensity of the interference signal from the reflected light from the reference arms 60 and the corresponding fibers of the sample arm 59 having the same bypass length. Determine the information.

Preferably, as shown in FIGS. 17-22C, the probe tip 55 comprises a scanning head 1 holding N optical fibers 8, where N is an integer as 2; Is greater than or equal to two. The N optical fibers 8 are preferably aligned around the scanning head 1 in parallel and at equal intervals. Preferably, the probe tip 55 comprises a mechanism 134 for moving the scanning head 1 such that each of the optical fibers 8 scans an angular range of N / 360 degrees. The moving device 134 preferably comprises the device 9 for linear motion which causes the scanning head 1 to rotate.

Preferably, the linear motion mechanism 9 has a fiber shaft holder having a shaft channel 31, wherein the shaft channel 31 extends axially along the holder, and N fiber channels 32 are aligned around the holder in parallel with the shaft channel 31 and comprise a twisting shaft, where the shaft moves within the channel and the holder rotates. The twisting shaft follows the shaft channel 31 snugly.

The scanning head 1 preferably has a socket head along the shaft and causing the scanning head 1 to rotate. Preferably the probe tip 55 is disposed on the scanning probe 50 to receive and follow the guide wire when the guide wire is in the vessel, bile duct, and possibly the GU organ. holder) 2. Guide wires are not needed in GI organs. Preferably, the endoscope 10 comprises a spring disposed between the scanning head 1 and the fiber shaft holder to allow the shaft to move back after the shaft moves forward.

The present invention relates to a method of imaging a blood vessel, GU, GI or bile duct of a patient. The method includes transmitting light from the light source 51 to the optical fiber array 28 including the plurality of optical fibers 8 in the patient's body. There is a step of transmitting light reflected from the patient by the patient. There is a step of receiving light from the array 28 at the detector D. There is a step of analyzing the light using the detector (D).

Preferably, there is a step of reflecting light from each optical fiber 8 using the corresponding reflector 56 associated with the fiber and reflecting light from the patient to the associated fiber using the reflector 56. Preferably, there is a step of moving each of the N optical fibers 8 comprising the optical fiber array 28 in an angular range of N / 360 degrees. Preferably, there is a step of applying a linear motion such that each of the N optical fibers 8 of the optical fiber array 28 moves this angular range.

The step of applying linear motion preferably extends axially along the fiber shaft holder with N fiber channels 32 arranged around the holder in parallel with the shaft channel 31 causing the holder to rotate. Moving the twisting shaft axially forward in parallel with the N optical fibers 8 via 31. Each of the N optical fibers 8 is disposed in each fiber channel of the N fiber channels 32. The twisting shaft follows the shaft channel 31 snugly as this shaft moves in the channel. Preferably, guiding the optical fiber array 28 along the guide wire received by the guide wire holder 2 when the guide wire is in the vessel, bile duct, and possibly in the GU system but not in the GI organ. There is.

The present invention relates to an apparatus for irradiating an object. The apparatus includes means for generating light. The apparatus includes means for analyzing light reflected from the object based on polarization, space, position or angle.

The means for analyzing are preferably described in the figures, in which polarization is found in FIG. 31, the position is found in FIGS. 1-30, the space is found in FIG.

The present invention relates to an apparatus for irradiating an object. The apparatus includes means for generating light. The apparatus includes means for analyzing light reflected from the object based on polarization.

The present invention relates to an apparatus for irradiating an object. The apparatus includes means for generating light. The apparatus includes means for analyzing light reflected from the object based on space.

The present invention relates to an apparatus for irradiating an object. The apparatus includes means for generating light. The apparatus includes means for analyzing light reflected from the object based on the angle.

The present invention relates to a method of examining an object. The method includes generating light. The method includes analyzing light reflected from an object based on polarization, space, position or angle.

The present invention relates to a method of examining an object. The method includes generating light. The method includes analyzing light reflected from an object based on polarization.

The present invention relates to a method of examining an object. The method includes generating light. The method includes analyzing light reflected from an object based on space.

The present invention relates to a method of examining an object. The method includes generating light. The method includes analyzing light reflected from the object based on the angle.

In operation of the present invention, the near infrared broadband light source 51 transmits a light beam to an input arm 58 of an array 28 type interferometer. The beam profile from the light source 51 is circular gaussian. The optical parts in front of the connector 1 make the beam profile linear and focus on the connector 1. The array 28 type interferometer consists of a plurality of fiber-based interferometers having four fiber arms connected to the opto-coupler 62. Light entering the input arm 58 is divided into a sample arm 59 and a reference arm 60, respectively. In the sample arm 59, the optical fibers 8 are distributed like an annular ring, and the light is focused in the target vessel perpendicular to the optical axis. At reference arm 60, RSOD introduces depth scanning and dispersion compensation. When the reflected light from both arms has the same optical path length, strictly speaking, interference occurs when within the coherence length. The strength of the interfering signal represents the structural information of the sample.

More specifically, with respect to input arm 58 and with reference to FIGS. 1, 2, and 3, a single beam emerges from S1 and is aimed by L1. At this point, the beam diameter is large enough to project all of the region of C1 throughout, but the beam is still circular. The circular lenses CL1 and CL2 change the beam profile linearly, which means that the beam is no longer circular, but this looks narrow from FIG. 2 and the beams after L1 in FIG. 3 are the same shape. ML1 focuses all light onto C1.

This is known as an open optic solution:

광 소스(S1)는 섬유 팁을 가지며 이 섬유 팁으로부터 광은 대기로 이탈한다.

The light source S1 has a fiber tip from which light escapes to the atmosphere.

L1은 조준 렌즈(122)이고, 그래서 광 소스(51)의 섬유 팁은 광을 조준하기 위해 L1의 초점의 뒤에 위치해야만 한다.

L1 is the aiming lens 122, so the fiber tip of the light source 51 must be located behind the focal point of L1 to aim the light.

CL1, CL2는 원통형 렌즈이다. 두 렌즈 간 격리거리는 각각의 원통형 렌즈(122) 초점 길이의 합이다. 이들은 단지 한 방향에서만 빔 크기를 감소시키는 망원경으로서 동작한다. 달리 말하면, 빔의 크기는 도 3으로부터 변하지 않는다.

CL1 and CL2 are cylindrical lenses. The isolation distance between the two lenses is the sum of the focal lengths of the respective cylindrical lenses 122. They act as telescopes that reduce the beam size in only one direction. In other words, the size of the beam does not change from FIG. 3.

ML1은 마이크로 렌즈 어레이(28)이고, 이것은 많은 작은 렌즈들을 갖는다. 작은 렌즈들 각각은 C1의 각각의 섬유 입구에서 초점을 가지도록 위치된다. C1은 ML1의 초점에 위치되어야 한다. 모든 마이크로 렌즈들은 동일한 초점 길이를 가진다. C1은 선형 섬유 어레이(28)이다.

ML1 is a micro lens array 28, which has many small lenses. Each of the small lenses is positioned to have focus at each fiber inlet of C1. C1 should be located at the focal point of ML1. All micro lenses have the same focal length. C1 is a linear fiber array 28.

In an alternative embodiment of the input arm 58 as shown in FIG. 4, known as a fiber based solution:

Light source S1 is connected to a single mode fiber, which is connected to a fiber splitter 50:50. S1.

The first fiber splitter is 1 * 2. Each output stage of the 1 * 2 fiber divider is connected to a 1 * 4 divider. SP1.

The second layer, each output stage of the 1 * 4 divider, is connected to a third layer, which is another 1 * 4 divider. SP2.

At the output of the third layer, the number of fibers is 32. 32 fibers form a linear fiber array 28. SP3.

Linear fiber array (28):

Each fiber is a single mode fiber, which can have different cutoff frequencies. The cutoff frequency depends on the central wavelength of the light source 51. In general, a central wavelength of 850 nm or 1300 nm is used for the light source 51. Each fiber is attached to each other, so they all together form a linear fiber array 28.

C1 is connected to the plurality of interferometers. Each interferometer consists of four fiber arms and an opto-coupler 62. At each end of each arm, there is a linear array 28 fiber connectors C1, C2, C3, C4. The incoming light is divided by the opto-coupler 62 and enters the sample arm 59 and the reference arm 60, respectively.

Regarding the sample arm 59, the sample arm 59 goes to the target vessel, as shown in FIGS. 5, 6, 7, 8 and 17. C2 is connected to a linear fiber array 28 that is annular at the other end. The total length of the arm is about 2m to 3m. When light leaves the annular tip F, it is aimed by L1 and then reflected outwardly by L2 from the probe.

Reflected light from the tissue follows back to L2 and L1 and is collected by the fiber tip. Thereafter, two reflected lights from the sample arm 59 and the reference arm 60 respectively create interference, which is detected by the array 28 detector D in the detection arm.

Sample arm 59 is adapted to pass through a target vessel, GI, GU, or bile duct. C2 is connected to a linear fiber array 28 having an annulus at the other end (probe tip 55) (FIG. 8). The total length of the sample arm 59 is about 1.5 m. The fiber array 28 is molded by the transparent cover 7 material (eg silicone resin or polymer).

In the annular probe tip F shown in FIG. 9, each fiber is bonded in the groove of the cylindrical polymer tube 53. The shape of each groove is shown in FIGS. 10 and 11. Each groove end has a reflector 56 tilted 45 degrees in the axial direction. Grooves are made by micro fabrication techniques. Each fiber has a lens 122 at the tip, which splices the multimode fiber to the same diameter as the diameter of the cladding 120 of the single mode fiber and then multimode to obtain curvature. It can be made by melting the ends of the fibers (Figs. 12 and 13). When the light leaves the fiber tip, the light is reflected outwardly by the reflector 56 at the end of the groove and then focused in the target tissue area. Reflected light from the tissue follows the same path as the incoming light and goes to the detection arm.

Micromachining or Micro-Electro-Mechanical Systems (MEMS) and nanotechnology are becoming increasingly popular for the development of improved biomaterials and devices (Macilwain C, "US plans large funding boost to support nanotechnology boom, " Nature , 1999; 400: 95, which is incorporated herein by reference). Similar to the fabrication method used for computer microchips, MEMS processes combine etch and / or material deposition and photolithographic-patterning techniques to develop microdevices (Madou, M., "Fundamentals of microfabrication," CRC Press : Boca Raton , 2002, which is incorporated herein by reference). MEMS has been proven promising in the pharmaceutical field for small mass and volume, low cost, and high functionality. Successful MEMS devices in medicine include smart sensors for cataract removal, silicon neurowells, microneedles for gene and drug delivery, and DNA arrays (Polla, DL, Erdman, AG, Robbins, WP, Markus, DT, Diaz-Diaz, J., Rizq, R., Nam, Y., Brickner, HT, Wang, A., Krulevitch, P., "Microdevices in Medicine," Annu . Rev . Biomed Eng, 2000; 02: ... 551-76; McAllister et al., 2000, all of which are incorporated herein by reference). However, most MEMS processes are virtually planar for two-dimension (2D) micro-features and are important for processing silicon materials. Other micromachining processes include laser beam micromachining (LBM), micro-electrical discharge machine (micro-EDM), and electron beam machining (EBM) (Madou). , M., "Fundamentals of microfabrication," CRC Press : Boca Raton , 2002), which is incorporated herein by reference). Micro-fabrication and micro-device development using metals, metal alloys, silicon, glass, and polymers has been described by the following (Chen, S. C, Cahill, DG, and Grigoropoulos, CP, "Transient Melting and Deformation in Pulsed Laser Surface Micro-modification of Ni-P Disks, " J. Heat Transfer , vol. 122 (no. 1), pp. 107-12, 2000; Kancharla, V. and Chen, S. C, "Fabrication of Biodegradable Microdevices by Laser Micromachining of Biodegradable Polymers," Biomedical Microdevices , 2002, Vol. 4 (2): 105-109 / Chen, S. C, Kancharla, V., and Lu, Y., "Laser-based Microscale Patterning of Biodegradable Polymers for Biomedical Applications," in press, International J. Nano Technology , 2002; Zheng, W. and Chen, S. C, "Continuous Flow, nano-liter Scale Polymerase Chain Reaction System," Transactions of NAMRC / SME , Vol. 30, pp. 551-555, 2002; Chen, S. C, "Design and Analysis of a Heat Conduction-based, Continuous Flow, Nano-liter Scale Polymerase Chain Reaction System," BECON , 2002, all of which are incorporated herein by reference).

For array 28, a stainless steel cylinder having a diameter of 1.5 mm is selected as the base material. If necessary, the diameter for vascular applications is 1.0 mm, larger and up to 3.0 mm for GU, GI, and bile duct applications. Both micro-grooves 54 (or 200 microns wide microchannels) and reflective surfaces use micro-electric discharge machining (micro-EDM) or a focused ion machined tool. Precision machining by micro-milling To increase the reflectivity of the reflective surface, the stainless steel cylinder is coated with deposited aluminum using electron-beam deposition.

With respect to the reference arm 60, shown in FIG. 14, the light is aimed by L1 after leaving the connector C4 and distributed spectrum by the grating G1 and focusing on the mirror GA1. do. By vibrating GA1, the optical path length is changed to achieve depth scanning.

There are many options for making reference arm 60 using existing techniques. A very simple form of reference arm 60 only has a mirror attached to a voice coil driven by a function generator with a sinusoidal wave. Light is reflected back by the mirror and the mirror position changes the optical path length. This path length change provides depth scanning of the target tissue because interference only occurs when both arms have the same optical path length. Preferably, the reference arm 60 is more complex than this simple one. It is called Rapid-Scanning Optical Delay (RSOD), which can provide fast depth scanning and dispersion compensation.

The linear array type beam starts from C4 and is aimed by L1. Mirror M1 reflects the beam to grating G1 which distributes the broadband source light into the spectrum. Spectrally distributed light is focused on a Galvono-scanning mirror GA1 by lens L2. The isolation distance between G1 and G2 determines the amount of color dispersion so that any material dispersion typically generated by the fibers can be compensated. The beam offset from the scanning mirror center determines the fringe frequency that appears after interfering two reflected lights. Reflected light from GA1 goes to L2, G1 and to M2. Next, the reflected light back along the incoming path is connected back to C4.

As shown in FIGS. 15 and 16, with reference to the detection arm, the light is aimed by L1 and is circular after leaving connector C3. The combination of CL1 and CL2 makes the beam appear linear (horizontally) in one plane. Micro-lens array ML1 allows light to be focused on array 28 detector D.

÷20 = 18

)의 각도 범위를 스캔하도록 설정된다. 반사 표면들(11)이 스캐닝 헤드(1) 상에 형성되고 그리고 각각의 광섬유들(8)의 중앙 측에 대해 45도 기울어져 있으며, 그래서 이들은 섬유 다발로부터의 광을 인도하고 그리고 투명 덮개(7)를 통해 광을 인도한다.As shown in FIGS. 17, 19A and 19B, the scanning probe 50 includes a scanning head 1, a fiber-shaft holder 3, a twist shaft 4, a transparent cover 7, a guide wire holder ( 2) and a mechanism 9 for linear movement. In this embodiment, the scanning head 1 is suitably configured to hold a fiber bundle with twenty optical fibers 8, which are arranged around the scanning head 1 in parallel and at equal intervals. In operation, each of the fibers is 18 degrees (360 degrees).

÷ 20 = 18

Is set to scan the angular range. Reflective surfaces 11 are formed on the scanning head 1 and are inclined 45 degrees with respect to the central side of each of the optical fibers 8, so that they guide light from the fiber bundle and the transparent cover 7 To guide the light.

The scanning head 1 is designed to provide 18 degrees of back-and forth rotation. The forward and backward rotation realizes the scanning function required by the OCT system. The mechanism of this forward and backward rotation is described below.

The fiber-shaft holder is substantially a multi-tube structure. It is formed of one shaft channel 31 extending along the central axis of the fiber-shaft holder and 20 fiber channels 32 arranged in parallel around the fiber shaft holder. The optical fibers 8 extend through the respective fiber channels 32. The shaft channel 31 has a round cross sectional area. At the higher end of the shaft channel 31, the shaft channel 31 is a passageway, the geometry of which is reduced from the rounded cross-sectional area to the rectangular cross-sectional hole 311. The reason for this structural design is explained with the description of the twist shaft 4.

The twist shaft 4 has a rectangular cross-sectional area, which is geometrically identical to the rectangular cross-sectional hole of the fiber-shaft holder 3. As indicated by its name, the shaft 4 is partially twisted along the shaft central axis and can be divided into an untwisted portion 41 and a twisted portion 42. In assembly, the shaft 4 passes through the rectangular cross-sectional hole of the fiber-shaft holder 3 which enables sliding back and forth through the rectangular cross-sectional hole. The relative motion of the twist shaft 4 and the surface of the rectangular cross-sectional hole forms a mechanism for realizing forward and backward rotation. Because when the twisted part 42 of the shaft 4 slides through the rectangular cross-sectional hole, the shaft 4 itself rotates along the shaft central axis to match the surfaces of the twist shaft 4 and the surfaces of the rectangular cross-sectional hole. For they are empowered to do so. In particular, the shaft 4 and the holder 3 constitute a mechanism 9 capable of transmitting linear motion in rotational motion.

The description now focuses on the scanning head 1. The scanning head 1 has a rectangular socket 12, which has the same cross-sectional area as that of the twist shaft 4. The rectangular socket 12 provides a channel covering the non-twisted part 41 of the twist shaft 4, and the non-twisted part 41 performs forward and backward movement inside the rectangular socket 12. Do it. The range of motion of the shaft 4 does not allow the twisted portion 42 to pass into the rectangular socket 12 of the scanning head (which results in geometric mismatches), but the twisted portion 42 is only of the fiber-shaft holder. Constrained to interact with rectangular cross-sectional holes. According to the foregoing description, the movement of the shaft 4 consists of a linear component V and an angular component ω. With regard to the geometry of the non-twisted portion 41 of the shaft 4 and the rectangular socket 12, the linear component V of the shaft movement (in spite of friction between the surfaces) is dependent upon the movement of the scanning head 1. It does not contribute but the angular component (ω) contributes. The scanning head 1 rotates back and forth in the rotational movement of the twist shaft 4, which also arises from the straight forward and backward movement of the twist shaft 4 with respect to the fiber-shaft holder 3. As a result, the scanning head 1 provides the forward and backward rotational motion transmitted from the forward and backward linear motion provided by the twist shaft 4.

The guide wire holder 2 is a module used to guide the scanning probe 50 towards the detected vessel, bile duct, and possibly the searched section of the GU application. For GI organs, guide wires are not commonly used. In operation, the guide wire 01, or “guide tissue”, is placed in advance along a particular route of human blood vessels, so that a track for the scanning probe 50 of the OCT system can be formed. The guide wire holder 2 constrains the scanning probe 50 so that it can only slide along the track formed by the guide wire 01. Scanning probe 50 is thus guided to the patient section to be searched.

The guide wire holder 2 and the holder 5 function as bearings of the scanning head 1. These constrain and stabilize the movement of the scanning head 1. In addition, a compression spring 6 is arranged between the scanning head 1 and the fiber-shaft holder 3. The spring 6 is compressed gently in the assembly, so that any potential axis of the scanning head 1 can push the scanning head 1 against the holder 5 and consequently cause an axial position error Δd. Eliminate exercise It is preferred that the spring 6 supplies torque between the scanning head 1 and the fiber-shaft holder 3. The spring 6 has both ends fixed on the scanning head 1 and the fiber-shaft holder 3 respectively. The spring 6 is twisted gently in the assembly. By this means, the spring can provide torque to the forward and backward rotation mechanism, so that not only the backlash of the rotation mechanism (for example due to the tolerance between the rectangular cross-sectional hole and the shaft) but also the resulting angular position error (Δθ) is removed.

It should be noted that the cross-sectional geometry of the shaft channel 31 is circular. With respect to the shaft channel 31, the twist shaft 4 is formed as a cylinder portion 43 at the end of the twist portion 42. Cylinder portion 43 and shaft channel 31 perform a piston-like movement. In the upward movement of the twist shaft 4, due to geometric differences, the cylinder part 43 is blocked at the edge 33 of the rectangular cross-sectional hole of the fiber-shaft holder 3 and the upper stopper for the twist shaft 4. stopper). On the other hand, a lower stopper 34 is arranged to prevent the cylinder portion 43 in the downward motion. The functions of the upper stopper and the lower stopper not only help to control the movement of the twist shaft 4 but also to control the angular movement of the scanning head 1.

There are many ways in the art that can provide power to the mechanism for pushing and pulling the twist shaft 4 to generate linear motion. However, hydraulic pressure, in particular hydraulic pressure, is preferred due to the following advantages.

1. Electrolyte electricity is not required for the scanning head 1 to energize the hydraulic linear mechanism 9. Some instruments, such as electromagnetic systems (or more specifically some micro-motors), require an electrical energy supply as well as additional components such as coils or magnets, which convert electrical energy into mechanical momentum. These are those installed in the scanning head 1 for conversion. The use of electricity is not desirable for medical problems, and the requirement for additional components increases the overall system complexity and technical difficulties in manufacturing. Some of the other devices, such as those containing piezoelectric materials, can be constructed in small spaces and simple structures, but they still need to accommodate large voltages to generate the required momentum.

2. The hydraulic mechanism 9 occupies a small space.

The structure of the hydraulic mechanism 9 is shown in Figs. 18A and 18B. The hydraulic mechanism 9 may simply be a fluid conduit leading a fluid such as water to push and pull a piston system consisting of a cylinder portion 43 and a shaft channel 31. In view of the fact that leakage through the gap of the piston system can result in undesirable problems, the hydraulic mechanism 9 preferably consists of a micro-balloon 91 made by a polymer thin film. do. As shown in FIGS. 18A and 18B, the twist shaft 4 is in the lower position when the balloon 91 is flat (FIG. 18A). As water is injected into the piston system, the balloon 91 swells, and the twist shaft 4 is pushed by an 18 degree spin toward the higher position (FIG. 18B). The necessary back and forth motion can occur by switching the flat and swollen state of the micro-balloon 91.

For a single fiber OCT system, a scan rate of 6 revolutions per second (6 Hz) is satisfactory [Andrew M. Rollins et al., "Real-time in vivo imaging of human gastrointestinal ultrastructure by use of endoscopic optical coherence tomography with a novel efficient interferometer design ", OPTICS LETTERS, Vol. 24, No. 19, Oct 1, 1999, which is incorporated herein by reference. This means that the half OCT system can provide at least six pictures to represent the cross-sectional data of the vessels. The scanning probe 50 has 20 fibers, so that a satisfactory scan speed can be reduced to 0.3 Hz (6 ÷ 20 = 0.3), which is much slower and much easier to be realized by a hydraulic drive system. Ideally, 15 photos / second would be required for optimal image resolution.

Rather than continuous rotation, the scanning probe 50 operates back and forth, so that the angular speed of the scanning head 1 is not constant even when the entire system reaches its steady state. During operation, therefore, it is important not only to detect the angle of the scanning head 1 but also to find the angular position to which the scanned data belongs. The angle of the scanning head 1 can be approximated simply by comparing the output force of the pumping system with the reference curve obtained from the previous experiment. More precise detection can be made by analysis of the feedback of the optical signal. For example, analyzing the optical Doppler effect of the feedback signal [Volker Westphal et al., "Real-time, high velocity-resolution color Doppler optical coherence tomography", OPTICS LETTERS, Vol. 27, No. 1, Jan 1, 2002, which is incorporated herein by reference] is another method.

The twist shaft 4 can be formed by precision CNC machining known in the industry. Thin, round shafts with a minimum of 1.0 mm can be used as intrinsic material before machining. For production, the two ends of the round shaft are clamped, the center part of which is precisely milled and four orthogonal planes on the center part are created. This plane defines the rectangular cross section of the twist shaft 4 as shown in FIG. 20A (in this step forms an elongated shaft). After milling, one of the two clamps holding the shaft is rotated with respect to the other clamp to twist the shaft at a certain angle about its central axis. The twisted part of the twist shaft 4 is formed.

After the twisting step, the rotated clamp is released to eliminate the elastic distortion of the shaft (the plastic distortion still remains), and then the clamp is tightened again. In the next step, as shown in Fig. 20B, the shaft is milled again on one side of the still-round portion, thereby creating another untwisted rectangular portion.

The cylinder part (which serves as a piston) is formed from the rounded part of the shaft. Precise lathering can also be used to fix the diameter and central axis of the cylinder part. As shown in Figure 20C, only a short portion of the shaft is needed. The excess part of the shaft is cut off.

As shown in FIG. 21A, the fiber-shaft holder 3 can be joined into two parts A and B. FIG. Part A is actually the body of the catheter. The cross section of the catheter is shown in FIG. 21B. The catheter can be manufactured by a cable extrusion technique that is generally applicable in the optical fiber industry (see Optical Cable Corporation's homepage). It should be noted that the central channel of the catheter is used to be the conduit for the delivery of the previously mentioned drive fluid. There are also several conduits used to guide the air flowing in and out of the probing tip to balance the air pressure inside the OCT system (during operation, the free volume inside the probing tip changes while the twist shaft 4 is moving). . The diameter of the conduits is equal to the diameter of the cylinder portion 43 of the twist shaft 4.

Part B in FIG. 21A is simply a plane with a fiber holding edge B1 and a rectangular central passage B2. This part can be made from metal using punching techniques commonly used in the industry. In assembly, parts A and B can be connected by glue, such as epoxy. The lower stopper necessary for constraining the twist shaft 4 at the lower position is formed with the formation of the micro-balloons.

Micro-molding with a polymeric material (such as SBS) can be used to make the scanning head 1. The process of micro-molding requires a set of micro-moulds. In this case, the fiber grooves 54 and the reflective surface 11 at the end of the fiber grooves 54 can be realized by a set of micro-molds consisting of 18 edges (FIG. 22A), Each of them has the geometry shown in FIG. 6B. The central rectangular channel can also be molded by a rectangular shaft made by the equipment for the manufacture of the twist shaft 4. For ease of assembly, the scanning head 1 may be provided in advance in the geometric form shown in FIG. 22C. Excess portions of the scanning head 1 aid in alignment to the optical fibers 8 and provide guidance. UV adhesive can be used to fix the position of the optical fibers 8. The excess part of the scanning head 1 is cut after assembly of the optical fibers 8.

In another embodiment, the laser beam heats at least three different locations on the surface of the micro-mirror 210, which is shown continuously as a disk in FIGS. 23-25. The micro-mirror 210 provides wabling corresponding to this kind of asymmetrical heating process, and the incident light (unlike the heating laser) can be redirected in a swaying manner.

The heating process corresponds to the rotation period of the micro-mirror 210 as required.

The micro-mirror 210 includes two layers. First layer 212 and second layer 214 (FIG. 23). At least one of the two layers may generate structural deformation (contraction or expansion) by application of laser light. If both layers are deformable by laser light, the sensitivity of the two layers to the same laser light is set differently with respect to each other. 24 shows a perspective view of the micro-mirror 210.

When the micro-mirror 210 is irradiated with a laser beam, there may be expansion or contraction in the layers. Since the degree of expansion or contraction inside the layers is different (only one layer is deformed or the two layers are deformed to different degrees), the structure of the entire micro-mirror 210 is twisted.

For example, in FIG. 25, when the section marked pie is irradiated with a laser beam, deformation as shown in FIG. 26 occurs.

The materials of the first layer 212 and the second layer 214 may be metal or photosensitive polymers.

In the case of a metal layer, for example, the first layer 212 is polysilicon and the second layer 214 is gold. The mechanism of expansion or contraction inside the layer is thermal expansion. The metal absorbs the energy of the laser beam and heats it up. Due to the different coefficients of thermal expansion of the two layers, this structure is twisted or bent. This consequently changes the mirror as shown in FIG.

In the case of photosensitive polymers, for example liquid crystal materials, the mechanism of expansion or contraction inside the layer is the phase change of the material. Under the irradiation of a laser beam, the molecules of the polymeric material undergo a phase change, where the chemical structure of the material is deformed and structural deformation takes place. Next, similar to the case of the metal layer, the degree of deformation of the two layers is different, and there is a twisting or bending effect in the structure of the micro-mirror 210 and in the result in FIG. 26. This leads to.

When this structure is twisted or bent by the application of laser energy, the surface of the mirror can be tiled in a particular direction as shown in FIG. Thus, the direction of the micro-mirror 210 can be controlled by controlling the laser energy input.

A method of controlling the application of laser light is to select a location on the micro-mirror 210 to be irradiated by the laser beam and to control the intensity of the laser. By controlling this position, it is possible to control the inclination direction of the mirror, and by controlling this intensity, it is possible to control the inclination angle of the micro-mirror 210.

25 and 26, by continuously changing the laser-splitting position (FIG. 27), the inclination direction of the micro-mirror 210 may be continuously changed (FIG. 28). That is, the micro-mirror 210 can be rotated by changing the position of the laser-splitting.

This is the mechanism for the rotation of the laser-driven micro-mirror 210.

With regard to the assembly of the entire OCT system (FIG. 29), the micro-mirror 210 is mounted on a base 21b connected to the tip end of the probe cover. There is no object between the fibers and the mirror. Fiber 1 used to direct the detection light is the same fiber as used in other examples of OCT probes. The detection light is redirected by the inclined surface of the micro-mirror 210, so that the inclined and rotating mirror can be used to scan the surroundings. Fiber 2 is used to direct drive-laser light. As shown, at least three fibers 2 are required. Fiber 2 alternately fires the laser, so they can produce the continuous tilt effect shown in FIGS. 27 and 28.

Other features of the laser-driven OCT probe are the same as those described in other embodiments. For example, the fiber and the fiber 2 are disposed in the fiber shaft holder 3.

After manufacture by semiconductor technology, known to those skilled in the art, the mirror is formed on a substrate (generally a silicon substrate). This substrate forms a base. Then, a small piece is cut using a dicer from the base carrying the mirror from the substrate. A small piece is mounted at the end of the tip by an adhesive (eg epoxy).

In this embodiment only one fiber 1 is sufficient to transmit the detection light. During operation, a circular scanning profile of the detection laser is realized. In this embodiment, illustrated in FIG. 30, the detection laser is not concentrated in the center of the mirror. Instead, the following remains constant: (1) d, the distance between the mirror center and the axis of detection light. (2) alpha, the angle between the mirror surface and the axis of detection light. An open-loop system is used for position feedback to properly adjust the periodic change in laser power from the three fibers 2 to achieve constant alpha and d.

Position control is more complicated than single-fiber 2 drive. In particular, the micro-mirror 210 requires a period of time that mechanically responds to the laser energy coming from fiber 2. Although it is known which fiber 2 emits laser power, the exact direction of the mirror surface information may not be clear.

The absolute position of the mirror is not really necessary. Instead, speed-control is used to control the rotation of the scanning mirror. For example, in the case of a mirror driven by a transmission cable rotated from the outside, the exact position of the mirror (which may be affected by the delay of the cable transmission due to the compliance of the cable) is of interest. no. The rotation period of the mirror is controlled so that the "relative position" of the mirror is known. After receiving the continuous data stream from the reflected detection laser, the cross-sectional image of the blood vessel is constructed by simply matching the data series to a period of rotation.

In this embodiment, the operation is similar. The other is that the micro-mirror 210 is not driven by the rotor but by three bimorph heat-deformable cantilever beams. This makes the control more complicated. If only one of the Fiber 2 fibers fires at once, scanning the circular profile that requires a mirror is very different, if not impossible. Instead, three fibers 2 need to fire together at different powers to bend the three cantilevers in different states at once to match the circular scanning profile. The three cantilevers are driven separately by the three fibers 2 so that they work together in a specific bending pattern that realizes a circular scanning profile on the wall with the blood.

In an alternative embodiment with respect to the micro-mirror 210, fibers 1 and 2 are reversed so that the therapeutic energy is preferably from a single fiber 2 disposed along the central axis of the tube. The plurality of fibers 1 are disposed around the circumference of the tube. When the micro-mirror 210 is irradiated with a laser beam from the fiber 2, the laser energy causes the mirror to bend. By varying the intensity of the laser or by pulsing the laser, motion is applied to the micro-mirror 210 which wires the probe tip (here the micro-mirror is attached) to move it back and forth and thus The plurality of fibers 1 for scanning the interior area of the patient can be moved back and forth.

Thermal expansion materials can normally produce an elongation of ˜5% for a temperature rise of 100 ° C. The length of the material inside the OCT is inherently 20 mm, which can thus lead to a thermal elongation of 1 mm. Polymers, including photosensitive polymers and shape memory polymers, can cause elongation or contraction induced by> 100% of light. The material inside the OCT is inherently 1 mm, so this can give rise to another 1 mm of thermal elongation.

Generally:

Optical tomography instruments can be specified by the bandwidth being resolved into the spectrum, which is equivalent to the number of cells that can be resolved into the spectrum. Each spectrum degradable cell has a width δv, so the number of cells degradable by the _instrument is N _instruments = Δv / δv, where Δv is the available optical bandwidth of the light source. The range of group-time delays that an optical tomography instrument can resolve is given by Δτ _instrument = 1 / δv. The smallest resolution group-time delay that an optical tomography device can resolve is Δτ _interference = 1 / Δv. The number of cells that can be resolved into the spectrum that can be resolved by an optical tomography device is given by N _devices = Δτ _device / Δτ _interference .

For one OCT A-scan into the object being imaged, the requirement for the number of spectrally decomposable cells is N _{A -scan} = Δz / L _C , L _C to c _g / Δv and Δz is the imaging depth, L _C (interference length), and c _g is the group velocity of light within the object.

N _{A - scan} = △ τ _{A- scan} △ v

Where [Delta] _A-scan = [Delta] z / c _g is the round-trip propagation time for light to propagate from the most superficial position and the deepest position (position to be imaged) within the object.

For some optical tomography imaging instruments (eg, those using narrow linewidth tunable laser sources or high resolution spectroscopy),

N _devices / N _{A -} = △ τ _{scan unit} / △ τ _{A- scan} = △ v / δv >> 1

The above condition can be described in three ways: a) The number of spectrally decomposable cells (N _device ) for a _device is much larger than that required for one _{A -scan} (N _{A -scan} ). ; 2) The range of group time delays (Δτ _instrument ) that the instrument can resolve is much larger than the group-time delay (Δτ _A-scan ) for a single A-scan; 3) The available optical bandwidth Δv of the light source is much larger than the spectral width δv of each resolution cell of the instrument.

Because the instrument can disassemble more cells than required for one A-scan, multiplexing techniques are used herein to efficiently utilize the information carrying capacity (bandwidth) provided by the optical tomography imaging instrument. Is provided.

The selection criteria of the multiplexing technique used can be derived in part by the ratio (N _devices / N _A-scan = Δτ _devices / Δτ _A-scans = Δv / δv). Larger ratios offer more choice of possible multiplexing techniques and provide more candidate regions (polarization, space, angle, time) (multiplexing here). Moreover, multiplexing spectral information into only one region (eg, space) is not the only predicted method. In general, additional spectral information may be decomposed into a plurality of regions (eg, polarization and space).

Specific embodiment:

떨어진 적어도 두 개의 입사 편광 상태가 간섭계에 입력된다. 혈과 벽 또는 신경 섬유 층과 같은, 샘플로부터 반사된 광의 편광 기호(polarization signature)는, 플라크 또는 병에 걸린 신경 섬유 층과 같은, 물질의 공지된 편광 기호와 비교된다. 반사된 광과 물질(이로부터 광이 반사됨)이 그 다음에 식별된다. PCT 특허 출원 번호 PCT/US2004/012773(이것은 참조 본 명세서에 통합됨)에서 설명되는 섬유 전달 시스템이 사용될 수 있다.A. Polarization: Additional spectral cells can be used to record information in the polarization region using the system shown in FIG. 90 on Poincare sphere

At least two apart incident polarization states are input to the interferometer. The polarization signature of the light reflected from the sample, such as blood and wall or nerve fiber layers, is compared to the known polarization symbols of the material, such as plaque or diseased nerve fiber layers. Reflected light and material, from which light is reflected, are then identified. The fiber delivery system described in PCT Patent Application No. PCT / US2004 / 012773, which is incorporated herein by reference, may be used.

The theory of operation of this method is explained using Mueller matrices or spectrally-resolved Jones calculus. By inserting FOSPI into the detection path of a Spectral Domain Optical Coherence Tomography (SD-OCT) instrument, the entire set of Stokes parameters of backscattered light at a certain depth in the specimen is determined by the interferometer's reference. It can be obtained without any other polarization control component in the / sample / detection path and without prior information of the polarization state of the light incident on the sample. In this configuration, two factors determine spectral control. One is the optical path length difference Δ (v) between the reference surface and the sample surface, introduced by the common-path SDOCT, and the other is the phase delay φ 1 (v) generated by the retarder system at FOSPI. ) And φ2 (v)). Thus, the output from the provided single channel polarization sensitive (PS) SD-OCT in the time-delay region is the convolution of the output from FOSPI and the output from SD-OCT. The Stokes parameter at the output of the interferometer

S _i = S _{i , 1} + S _{i , 2} + S _{i , i}

의 각도에서 배향(oriente)된 빠른-축을 갖는 복굴절 샘플을 고려하자. 그러면, 샘플(S_{i ,2})과 간섭(S_{i ,i})으로부터의 광의 스토크스 파라미터는 기준으로부터의 광의 스토크스 파라미터의 항(S_{0 ,1}, S_{1 ,1}, S_{2 ,1}, S_{3 ,1})으로 계산된다.Where the first two terms are Stokes parameters of light from the reference path and the sample path, respectively, and the last term is the contribution of interference. Phase delay (δ)

Consider a birefringent sample with a fast-axis oriented at the angle of. Then, the Stokes parameters of the light from the sample _{Si , 2} and the interference _{Si , i} are the terms S _{0 , 1} , S _{1 , 1} , S _{2 , 1} , S of the Stokes parameters of the light from the reference. _3, is calculated by _1).

Where r _s is the reflection coefficient of the sample and Δ is the optical path length difference between the sample and the reference path. Here, the terms comprising the trigonometric function of Δ represent interference between light from the reference and sample paths.

Next, the measured intensities from SDOCT through FOSPI for the birefringent sample are as follows for the interfering signal.

The Fourier transform of equation (3) provides seven components in the positive optical path length difference region concentrated in Δ, Δ ± φ2, Δ ± (φ2-φ1), and Δ ± (φ2 + φ1), respectively. . The inverse Fourier transform of each component is as follows.

After S _{1 , i} / 8 is obtained by shifting the phase by -φ ₂ , the real part of S _{0 , i} / 4 and equation (5) is obtained by comparing the real part of equation (2) with equation (4). Get Similarly, S _{2 , i} / 8 and S _{3 , i} / 8 are respectively suitable phase shifts-(φ ₂ -φ ₁ ) and-(φ ₂ + φ ₁ ) for equations (6) and (7), respectively. It can then be obtained by subtracting equation (7) from equation (6) to take the real part and adding equation (6) and equation (7) to take the imaginary part. Furthermore, a simple arithmetic operation can obtain the phase retardation δ due to the birefringence of the sample without knowing the incident polarization state. The real part of equation (4), the imaginary part of equation (5), and the imaginary part of subtracting equation (7) from equation (6) are-△,-(Δ + φ ₂ ), and-(△ + φ, respectively). After the phase shift by ₂ -φ ₁ ), it is as follows.

Using trigonometric identities, we obtain

에서 90

까지 5

증분으로 회전된다. 예측된 단일-패스 위상 지연인 34.06

± 2.68

는 제조자의 사양(31.4

)으로부터 추론된 값과 일치한다. 예측된 빠른-축 각도는 도 4(b)에 도시되어 있고 그리고 복굴절 샘플의 배향에 대하여 도시되어 있다.The phase delay due to birefringence [FIG. 36] and the fast-axis angle of the birefringent sample [FIG. 37] are predicted from the interference between the backside of the birefringent sample and the backside of the glass window by using the above equations. For these measurements, the birefringent sample is zero

From 90

Up to 5

Rotated in increments. 34.06, predicted single-pass phase delay

± 2.68

The manufacturer's specifications (31.4

Matches the value deduced from The predicted fast-axis angle is shown in Figure 4 (b) and for the orientation of the birefringent sample.

This shows the practical realization of polarization multiplexing.

B. Spatial or Lateral Positions: Additional spectral cells can be used to record information in the spatial or lateral position region using the system shown below.

1. Conventional multiple fiber method: (described above)

2. Spatially scanned light:

A drawing of experimental equipment of a fiber-based spatially multiplexed and swept source OCT (SM-SS-OCT) system is shown in PCT Patent Application No. PCT / US2004 / 012773, which is incorporated herein by reference. 32 is shown using the system described in wherein the top is preferably rotated at least 100 times for each position.

Tunable lasers and spectrum analyzers (TLSA 1000, Precision Photonics, Inc.) operating in the 1520-1620 nm wavelength range (λ ₀ = 1570 nm) with a FWHM spectral line width specified at 150 KHz are used as illumination sources and are pseudo An optical isolator is provided to protect the laser from spurious reflectiions. The laser output is connected to one arm of a 2x2 fiber-based coupler (interferometer). The 50% -50% coupler splits this beam into two nearly identical parts used in the reference and sample arms, respectively. The reference arm simply consists of a fixed mirror having a fixed path length and reflecting the entire incident light back to the fiber-based coupler. Light exiting the sample arm of the interferometer is aimed and scanned throughout the sample by a scanning galvanometer and focusing lens. Scanning galvanometers and focusing lenses are used to quickly scan the lateral position of the tissue. The TLSA 1000 completes one complete wavelength sweep in approximately one second. Within this time, the galvanometer is programmed to sweep all side positions of the tissue a few hundred times. The light returned from the sample interferes with the light from the fixed reference in the fiber-based interferometer, and the resulting spectral interference signal (due to the change in path length between the sample and the reference reflection) is located within the detection arm of this system. Detected by the photodetector. The electrical output is digitized and a Non-Uniform Fourier Transform (NUFT) of each A-line spectral data provides a depth profile of sample reflections. 34 and 35 are images of 100 micron thick slides recorded using a spatially multiplexed OCT system. This image is of the same object (microscope cover glass) for only one image (FIG. 34) and the intensity of the light returned from the sample is displayed on a linear greyscale while in another image (FIG. 35) It is displayed according to the logarithm.

C. Angle: Additional spectral cells can be used to record information in the angular area using the system shown in FIG. 33.

_i)와 후면산란 각도(β_j)에 대응하여 각각 형성된다. 그 다음에 스펙트럼 영역에서의 광 강도는 광수신기를 통해 전압으로 변환되고, 이것은 ADC 보드에 출력하고, 컴퓨터에 판독된다. 이 시스템은 표본 안팎의 이산 광 경로(discrete light paths)의 위상-민감 각도 분해 이미지화를 가능하게 한다. 공간-공간 주파수 변환(예를 들어, 이-차원 퓨리에 변환)을 사용하여 측면 구조들이 서브-파장 분해능으로 이미지화될 수 있다.33 illustrates a multiple fiber angle-domain OCT system. The output of the frequency-swept source A is split into n fibers through divider B. Light passes through circulators C, is aimed at, focused through a lens, contacts tissue, and then reflected into any of the plurality of fibers. A reference reflector for each path is introduced into each fiber segment. For example, the reference reflector may be located at the terminal at the terminal end of each fiber segment. For each i th input fiber segment, interference is formed between the light backscattered from the tissue and into the j th fiber and the reference reflection from the j th fiber. For N fibers, N ² Interference fringes have an angle of incidence (

_i ) and the backscattering angle β _j are respectively formed. The light intensity in the spectral region is then converted into a voltage via a photoreceiver, which is output to the ADC board and read by a computer. This system enables phase-sensitive angular resolution imaging of discrete light paths inside and outside the specimen. Side structures can be imaged with sub-wavelength resolution using a spatial-to-space frequency transform (eg, a two-dimensional Fourier transform).

D: Spatial-angle combining (e.g., x dimension-space, y dimension-angle): The spatial and angular dimensions can be combined to form a system using additional spectral cell images for both space and angle. . For example, additional spectral cells can be used to record position information in one dimension (eg x) and angle information in the orthogonal dimension y.

Although the present invention has been described in detail in the foregoing embodiments for purposes of illustration, it should be understood that such details are for illustrative purposes only and in addition to those which may be described by the appended claims. Various modifications may be made by those skilled in the art without departing from the spirit and scope.

Claims (34)

As an endoscope for patients, A light source; Means for generating light; An optical fiber array comprising a plurality of optical fibers configured to be disposed in the patient body, the optical fiber array transmitting light from the light source to the patient and transmitting light reflected by the patient from the patient, and The plurality of optical fibers of the array are in optical communication with the light source; And And a detector for receiving light from the array and analyzing the light, wherein the plurality of optical fibers in the array are in optical communication with the detector. The method of claim 1, A patient endoscope comprising a tube, wherein the plurality of optical fibers are disposed around the tube. The method of claim 2, The tube has grooves extending longitudinally along the tube, wherein one of the plurality of optical fibers is disposed in each of the grooves. The method of claim 3, wherein A probe tip having a reflector disposed in each groove, the reflector reflecting light from the optical fiber in the groove when the reflector is in the patient body and when the array is in the patient body A patient endoscope for reflecting light from the optical fiber to the. The method of claim 4, wherein And said light source comprises a tunable laser source and means for directing light from said light source to said plurality of optical fibers of said array. The method of claim 5, wherein The optical fiber is single mode, has a core and a cladding is disposed around the core, and at its tip has a lens for focusing light from the core to the reflector and focusing light from the reflector to the core. Endoscope for patients. The method of claim 6, And said array comprises a transparent cover. The method of claim 7, wherein The means for generating light comprises an input arm, the array comprises a sample arm, and the detector comprises a reference arm and a detector arm; And the input arm, the detector arm, the sample arm, and the reference arm together form an interferometer. The method of claim 8, The reference arm using RSOD to introduce depth scan and dispersion compensation for the interferometer. The method of claim 9, And an opto-coupler for optically coupling the light from the input arm to the corresponding optical fibers of the sample arm. The method of claim 10, And the detector determines structural information for the patient from the intensity of an interference signal from reflected light from corresponding fibers of the sample arm and the reference arm. The method of claim 11, Wherein said probe tip comprises a scanning head holding N optical fibers, wherein N is an integer greater than or equal to two. The method of claim 12, And said N optical fibers are aligned in parallel and at equal intervals around said scanning head. The method of claim 13, And the probe tip includes a mechanism for moving the scanning head such that each of the optical fibers scans an angular range of 360 / N degrees. The method of claim 14, The moving instrument includes an instrument for linear motion that causes the scanning head to rotate. The method of claim 15, The linear motion mechanism comprises a fiber shaft holder having a shaft channel, wherein the shaft channel extends axially along the holder, and N fiber channels are aligned around the holder in parallel with the shaft channel, And a twisting shaft, wherein the twisting shaft conforms snugly to the shaft channel as the twisting shaft moves within the shaft channel and the holder rotates. The method of claim 16, And the scanning head is fitted with the shaft and has a socket head to allow the scanning head to rotate. The method of claim 17, And the probe tip includes a guide wire holder disposed on the scanning probe to receive and follow the guide wire when the guide wire is in the vessel, bile duct and possibly GU. The method of claim 18, And a spring disposed between the scanning head and the fiber shaft holder to move the shaft back after the shaft moves forward. The method of claim 3, wherein And a photoactive material, wherein said photoactive material changes at least a portion of said tube when light is received by said photoactive material. As a method of imaging a patient's blood vessels, Transmitting light from a light source within the body of the patient to an optical fiber array comprising a plurality of optical fibers; Transmitting the light reflected by the patient from the patient; Receiving light from the array at a detector to convert a signal; And Analyzing the light signal with a processing element. The method of claim 21, Reflecting light from each optical fiber with a corresponding reflector associated with the fiber and reflecting light from the patient with the reflector with the reflector. The method of claim 22, Moving each of the N fibers comprising the fiber array in an angular range of 360 / N degrees. The method of claim 23, Applying a linear motion such that each of the N optical fibers of the optical fiber array moves the angular range. The method of claim 24, Applying the linear motion, A twisting shaft with the N optical fibers through the shaft channel extending axially along the fiber shaft holder with N fiber channels arranged around the holder in parallel with the shaft channel causing the fiber shaft holder to rotate. Axially moving forward in parallel, wherein each of the N optical fibers is disposed in a respective fiber channel of the N fiber channels, and the twisting shaft is moved when the twisting shaft moves within the channel. And follow the shaft channel snugly. The method of claim 25, Guiding the optical fiber array along the guide wire received by the guide wire holder when the guide wire is in the vessel, bile duct and possibly GU. Device for inspecting an object, Means for generating light; And Means for analyzing light reflected from the object based on polarization, space, position or angle. Device for inspecting an object, Means for generating light; And Means for analyzing light reflected from the object based on polarization. Device for inspecting an object, Means for generating light; And Means for analyzing the light reflected from the object based on space. Device for inspecting an object, Means for generating light; And And means for analyzing the light reflected from the object based on an angle. As a way of examining an object, Generating light; And Analyzing light reflected from the object based on polarization, space, position or angle. As a way of examining an object, Generating light; And Analyzing light reflected from the object based on polarization. As a way of examining an object, Generating light; And Analyzing light reflected from the object based on space. As a way of examining an object, Generating light; And Analyzing light reflected from the object based on an angle.

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